1. Field of Invention
The present invention relates to a hydromount absorbing and alleviating vibration of driving components such as an engine, a power train, a transmission, and the like of a vehicle, and more particularly, to a three point supporting bush type hydromount in which inner pipes are disposed in a horizontal direction of a vehicle frame.
2. Description of Related Art
In general, suspension parts of a vehicle act to control displacement and perform a vibration-proof operation for a power plant including an engine and a transmission.
Vibration phenomena of the vehicle include the shaking of a vehicle body when the engine starts and stops, the vibration of the vehicle body in idling, the vibration of the vehicle body when the engine is in high RPM, the vibration by a bump, the shaking of the vehicle body when a high load is given, an impact when a sudden change occurs in acceleration or shifting, interference and breakage by excessive displacement, etc.
Origins of the vibration include a torque fluctuation when the engine is in low RPM, the vibration of a power plant by inertial force and couple force by rotary motion of a crank shaft when the engine is in low RPM, and the vibration of a power plant by couple force and thrust force by a driving system joint angle, etc., in the case of a low-frequency region (30 Hz or less).
In addition, the origins of the vibration include the vibration of a power plant by inertial force and couple force by rotary motion of the crank shaft when the engine in high RPM, the engagement vibration of gears in the transmission, the vibration of a cylinder block in combustion, the moving valve system vibration of an engine, the bending of a crank shaft, torsional vibration, the bending of a power plant, etc., in the case of a high-frequency region (30 Hz or more).
The vibration causes noise and the noise is transferred up to the interior of the vehicle via the vehicle body to be a chief cause in deteriorating ride comfort.
Therefore, when driving components such as the engine, the power train, the transmission, etc. are mounted on an engine room, a mount capable of supporting the driving components while withstanding their weights and absorbing and alleviating vibration so as to transfer minimum vibration to the vehicle body is mounted.
Since the mount should alleviate/absorb the vibrations of the driving components and withstand load weights of the driving components, the mounting locations, the number, and the structures of the mounts are designed by considering the weights, structures, chasses, body structures, etc. of the driving components.
When the mounts support the engine, the power train, and the transmission, the mounts are referred to as an engine mount, a power train mount, and a transmission mount, respectively. The engine of the vehicle including the transmission is connected to lower and side frames of the vehicle body by the mounts.
The structure of the mount is divided into a rubber mount and a hydromount (hydraulic mount).
The rubber mount has a structure in which elastic rubber is interposed between an upper plate and a lower plate and damps vibration and noise by using the elastic rubber.
The hydromount includes a liquid chamber part and a space part of a diaphragm, and has a structure in which a liquid chamber of the liquid chamber part is pressed to store fluids in the diaphragm through an orifice and damps vibration and noise through the fluids.
The mount used particularly for the transmission among the mounts is mounted on the vehicle body in a four point inertial supporting method or a three point inertial supporting method. In the mount mounted in the four point inertial supporting method, a mounting direction of an inner pipe of the mount is a forward and backward direction of the vehicle, while as shown in an outline diagram of a known three point inertial mount of FIGS. 1A and 1B and a perspective view of the known three point inertial mount of FIG. 2, a direction of an inner pipe 102 of the mount 101 mounted on a vehicle frame 100 in a three point inertial supporting method is a horizontal direction of the vehicle frame 100 in order to enhance noise and vibration and an amount of forward and backward rubber when the vehicle is accelerated. Therefore, since the three point mount has mounting locations less than the four point mount by one, the structure of the three point transmission mount needs to be designed as the hydromount structure in order to solve a disadvantage in which ride comfort is relatively worse as the movement of the transmission is larger.
However, when the direction of the inner pipe of the hydromount is designed as the horizontal direction of a vehicle, since the inner pipe cannot withstand excessive input in the forward and backward direction of the vehicle, the diaphragm formed by a thin film having low hardness, which is provided in the mount, is broken due to lack of durability, and as a result, the hydromount may lose the hydromount function.
The information disclosed in this Background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.